Utility pole assembly

ABSTRACT

Ceramic elements which can be clamped together by means of a tension rod so as to form a cross-arm assembly for a utility pole. The elements are provided with recesses which receive electrical conductors, with clips being provided so as to retain the conductors within the recesses. The elements thus provide physical support for the conductors and also form the insulating medium for the conductors.

BACKGROUND OF THE INVENTION

The present invention relates to a utility pole assembly including across-arm which provides support for electrical conductors. Inparticular, the present invention relates to a utility pole assemblyincluding a cross-arm that is both insulating and supportive.

Although the present invention will be described with particularreference to a cross-arm assembly of ceramic bricks or blocks which aremanufactured from essentially non-conducting material, the scope of thepresent invention is not so limited and may extend to other applicationsof the bricks or blocks and cross-arm assembly and to other forms of thesupport assembly.

Cross-arms for utility poles, such as those carrying electricalconductors and insulators, are most usually made of wood and areprovided with metal fittings. The wood deteriorates in time, caused bywater impregnating the matrix of the wood thus destroying its structure.In addition, the wooden poles when wet or impregnated with moisture canbe electrically conductive, particularly so when metal fittings are usedto secure the cross-arms. Thus, existing cross-arms of power poles haveat least two deficiencies, that of premature ageing and deteriorationnecessitating replacement at a high cost of both labor and replacementmaterials, and that of the unwarranted conduction of stray currents toundesirable parts of the pole assembly which presents a safety problemsince it may cause shock or other injuries to operators or people in thevicinity of the poles.

Therefore, it is an aim of the present invention to at least provide across-arm assembly or cross-arm element which at least alleviates one ofthe problems of prior art cross-arms or cross-arm elements.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided anelement suitable for use in a cross-arm assembly for a utility pole forsupporting an electrical conductor in an insulated condition, in use,comprising a body portion and a top portion, said top portion beingprovided with conductor support means for supporting an electricalconductor in position in an insulated condition and wherein said bodyportion is provided with means for connecting said element to adjacentsimilar elements for forming said assembly.

According to another aspect of the present invention there is provided across-arm assembly for a utility pole for supporting at least oneelectrical conductor in an insulated condition, in use, comprising aplurality of similar elements of a substantially insulating materialinterconnected together so as to form the cross-arm, each of saidelements having a body portion and a top portion, said body portionbeing provided with means permitting adjacent ones of the elements to befastened together and the top portion being provided with means tosupport the electrical conductor, and wherein at least one of theelements is connected to the pole in use.

According to another aspect of the present invention there is provided autility pole having at least one cross-arm assembly wherein thecross-arm assembly comprises a plurality of similar insulating elementsof the form defined above.

DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of example withparticular reference to the accompanying drawings in which:

FIG. 1 is a perspective view of one form of the ceramic block of thepresent invention;

FIG. 2 is a cross section view of the block of FIG. 1 taken along theline 2--2 of FIG. 3;

FIG. 3 is a view of a utility pole having a cross-arm assembly inaccordance with the present invention;

FIG. 4 is a cross-section view along 4--4 of FIG. 3; and

FIG. 5 is a more detailed front view of the block in the cross-armassembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1 there is shown a block 2 made of a ceramic material which isnon-conductive and may be glazed or impregnated with polymer so as to bemoisture- or water-proof. The composition of the ceramic block is suchthat even if the glaze is damaged or deteriorates, water may not ingressinto the matrix of the material to any significant extent and certainlynot to such an extent that substantial leakage currents may be conductedthrough the body of the block.

The block 2 has a base 4 being generally cuboidal in shape but havingcurved longitudinal edges 6. The underside of the block 2 is formed witha shallow concave recess between the edges 6 which extends in thelongitudinal direction of the block. The block 2 has a curved topportion 5 having a relatively thin neck portion 8 and a relativelythicker head portion 10. The top portion 5 of the block 2 has atransversely extending straight groove 12 which extends through both theneck and head portions. In use, an electrical conductor 14, such as oneof the wires of the electrical supply network, is received in thetransverse groove. A slidable locking clip 16 of generally C-shapedcross-section and of complementary contour to the upper contour of thehead portion 10 is located on the head portion above the groove 12. Theclip 16 can be slid along the head portion so that the conductor 14 maybe placed in groove 12. However, once the conductor 14 is located in thegroove 12, the locking clip is slidably moved to span the groove 12 andthereby retain the electrical conductor in the groove, as shown in FIGS.2 and 5.

The base 4 of the block has a longitudinally extending bore 20 locatedat or near its center for receiving a tensioning rod 22 or similartensile member therethrough so as to secure adjacent blocks together (aswill be described in more detail later). The reinforcing rod or tensilemember is preferably coated or provided with suitable surface coating orplastic insulating sleeve so that in the event that water enters thecentral bore 20, the rod 22 will not conduct electricity. Further thecoated rod will not undergo electrolysis reactions, such as rust orother corrosive mechanisms, which would tend to cause deteriorationthereof and thus loosen the cross-arm assembly.

FIGS. 3 to 5 show a cross-arm assembly 23 mounted on a utility pole 24,typically a timber pole of conventional form, by a bracket 26. Inassembly of the cross-arm assembly 23, the rod 22 is passed through thealigned bores 20 of the blocks and tensioned by means of tightening nuts25 so as to apply compressive forces to the blocks so as to retain themin a rigid structure. Metal plates 52 are located at the free ends ofthe blocks in the assembly 23 to evenly distribute the load applied bythe tensioning rod 22.

The cross-arm assembly 23 includes spacing means including a pair ofresilient washers 44 and spacer 46 sandwiched therebetween locatedbetween adjacent blocks. The washers and spacers may be formed fromrubber or plastic material or material having a surface coating ofsilicone rubber or sealer. Each washer 44 preferably extends verticallyabove the place of the upper surfaces of the heads of the blocks so thatbirds or workman are unlikely to inadvertently contact two adjacentconductors so as to create a short circuit and thereby damage orotherwise disrupt the power supply or conductors or pole assembly. Also,each washer 44 preferably extends below the lower surfaces of theblocks.

One form of the bracket 26 is shown in FIG. 4 and comprises a firstportion 29 which is generally U-shaped in cross section and has one arm30 substantially longer than and interconnected to the other arm 32 by aweb portion 34 extending substantially at a right angle from the pole.In use, the cross-arm assembly 23 is located in the first portion of thebracket with the central block snugly engaged by the arms 30 and 32 andweb portion 34. A second portion 36 of the bracket has a first flangeportion 38 which abuts, in use, against the upper end of arm 30 of thebracket portion 29. The second portion 36 includes a top flange portion40 arranged at a right angle to first portion 38 for contacting theupper surface of the head portion 5 of the block 2 and an inclined sideportion 42 which engages the upper end of the shorter arm 32 of thefirst portion 29 of the bracket to thereby define a substantiallyenclosed loop surrounding the block 2. Thus, the cross-arm assembly 23,in accordance with the present invention, is clamped within the bracket26 and the bracket is secured to the top of the pole by the bolt and nutassembly 28 as shown in FIG. 4.

A pair of forestays 48 are optionally provided to further secure thecross-arm assembly 23 against pivotal movement relative to the pole 24.The lower ends 49 of the stays are secured to the pole 24 and extendfrom the pole to the cross-arm. The cross-arm is provided with mountingplates 50 which depend downwardly therefrom and which are clampedbetween adjacent blocks 2. The mounting plates preferably replace thespacers 46 at the selected locations for connection to the stays 48.

In another embodiment, rear stays (not shown) are located on theopposite side of pole 24 to forestays 48 and extend from the pole 24 tothe cross-arm 23 in a manner similar to forestays 48 and plates 50. Therear stays are substantially in the common plane of blocks 2 forming thecross-arm assembly 23 to prevent twisting or rotation of the cross-armabout the central longitudinally extending axis of the pole.

In one embodiment the block is 300 mm long, 100 mm in height and 90 mmwide.

Those skilled in the art will appreciate that the invention describedherein is susceptible to variations and modifications other than thosespecifically described. It is to be understood that the inventionincludes all such variations and modifications which fall within itsspirit and scope. For instance, each block may include two or moregrooves 12 for receiving conductors.

What is claimed is:
 1. A utility pole assembly, said assemblycomprising:a utility pole, a cross-arm, a bracket connecting thecross-arm to the pole and a pair of stays which extend from the pole tospaced locations on the cross-arm, said cross-arm comprising a pluralityof ceramic elements each including a bore therethrough, said elementsbeing arranged so that their bores are aligned, said cross-arm includingspacing means located between adjacent elements, each spacing meanshaving openings therethrough, said cross-arm further including a tensionmember which passes through said bores and said openings and clamps saidelements together, and wherein each element comprises a body having atop portion with conductor support means for supporting an electricalconductor which in use extends transversely relative to the cross-arm,said bracket having an opening therein which is generally complementaryin shape to the body so that the cross-arm can extend therethrough andbe firmly clamped by the bracket to the pole.
 2. A utility pole assemblyas claimed in claim 1, wherein the underside of each element includes ashallow concave recess which extends in the longitudinal direction ofthe cross-arm.
 3. A utility pole assembly as claimed in claim 1 whereineach body is generally cuboidal in shape.
 4. A utility pole assembly asclaimed in claim 3 wherein each conductor support means includes arecess which extends transversely relative to the longest dimension ofthe body and wherein, in use, a conductor is located in the recess.
 5. Autility pole assembly as claimed in claim 4 wherein each recess is opento the upper surface of the top portion and the conductor support meansincludes a clip which is resiliently engageable with the top portion andoperates in use to hold a conductor captive in the recess.
 6. A utilitypole assembly as claimed in claim 5 wherein the top portion includes arounded head and the clip is slidable along the head.
 7. A utility poleassembly as claimed in claim 1 wherein each spacing means comprises apair of resilient washers and a spacing element sandwiched therebetween,the tension member passing through the washers and spacing element.
 8. Autility pole assembly as claimed in claim 7 wherein said washers projectabove and below the top and bottom surfaces of the elements of thecross-arm.
 9. A utility pole assembly as claimed in claim 1 wherein eachstay is connected to the cross-arm by means of a stay mounting bracketwhich is clamped between adjacent elements of the cross-arm.